I have recently set up our website so that I can put it in read-only mode (using the Read Only Mode module) when doing maintenance, such as upgrades and code pulls, however, this is a Drupal function only and I noticed that while in read-only mode, CiviCRM front-facing forms, such as CiviContribute forms, as well as backend functions are still available.
Is there a way to either put CiviCRM into read-only mode or turn off/deactivate the CiviContribute forms? I have written a bash script that runs all my update/upgrade processes and would like to find a way to do this using drush. For staff, I'm thinking of just deactivating the link to CiviCRM in the administrative menu, but I am most concerned with making sure users can't process transactions and write to the database during down-time.
I'm on CiviCRM 5.1.0 and Drupal 7.59